Aileron device



Sept. 19, 1939. E. F. zAPARKA 2,173,674

AILERON DEVICE l Original Filed June 7, 1953 3 Sheets-Sheet l Sept. 19, 1939. YF. F. ZAPARKA AILERON DEVICE 3 Sheets-Sheet 2 Original Filed June 7, 1933 E. F, ZAPARKA AILERON DEVICE Sept. 19, 1939.

original Filed June 7, 193s s sheets-sheet s Ffa/0. f

dtfonwq il Patented Sept. 19, 1939 UNITED VSTATES PATENT OFFICE AILERON DEVICE Application June 7,1933, serial No. 674,729

^ Renewed January 13, 1937 17 Claims.

My invention relates to ailerons, Aand more particularly to ailerons which are balanced so that. it requires gradually increasing control stick forces to move them from the neutral position.

Though I am not to be limited to any particular location of the ailerons, the ailerons I have shown are of the type illustrated andde- -scribed in my application Serial No. 653,918, iiled January 27, 1933.

The present application deals with the construction of the aileron per se, and the location of the aileron as specifiedin Serial No. 653,918 is not restrictive in considering claims in this application, except as the language imposes such 5 limitations.

Heretofore when a pair of ailerons moved in opposite directions from the neutral position, there was a soupy action at the control stick for the first few degrees of movement of the pair of Zap ailerons from the neutral position. This soupy action was followed by a very sharp increase in the stick forces necessary to move the pair of Zap ailerons when the change'from the vertical angle became great.

It is one of the objects of this invention to provide ailerons such that the forces necessary to move the'pair of Zap ailerons through increasing plus and minus angles of attack is considerably less than for a pair of normal Zap ailerons.

' It is a further object of this invention to provide ailerons in which the center of pressure shift at varying angles of attack creates favorable hinge moments. V

A still further object of my invention is to provide aileron constructions which areso pivoted that the pivot shifts with the angular movement of theaileron so that the shift inicenter of pressure is compensated largely by varying the moment arm'between the center of pressure and the point of pivoting. d

Still another object of my invention is to projvide ailerons so constructed that the tendency for the center of pressure to shift on any one designed area of an aileron in one direction is compensated for by shift of center of pressure in the opposite direction on another designed area, whereby there is a tendency for these opposite shifts in center of pressure on the different de- -signed areas to at least in part neutralize each other.

In the drawings:

vFigure 1 is a top plan viewA of an airplane equipped with one form of my aileron;

Fig. 2 is a detail view inside elevation of a lthe different positions of the aileron being indicated by dottedlines;

Fig. 6 is a detail view in side elevation and partly in section showing anotherv form of aileron, the diiierent positions being indicated in' dotted lines;

Fig. '7 is a detail view in side elevation andA partly in section showing another form of aileron, the different positions being indicated in dotted lines;

' Fig. 8 is a detail view in side elevation and partly in section showing another form of aileron, the different positions being indicated lin dottedA lines;

Fig. 9 is a detail view in side elevation and partly in section showing another form of aileron, the different positions being indicated in dotted lines;

Fig. 10 is a side elevation of another modication of my aileron, the different positions being indicated in dotted lines;

Fig. 11 is a rear elevational view of a wing showing a different form of my aileron in posi-y tion above the wing;

Fig. 12 is a detail view in side elevation of the aileron illustrated .in Figure 11. v

Referring to the drawings, in Figures 1 and 2 I have shown a form of my aileron having a front slot construction. In Figure 1 I have shown Aan aileron having a fuselage I, a motor 2, propeller 3 and wings 4. Above the wings 4 and near the trailing edge thereof, as shown in the drawings, I have mounted ailerons 5. 'I'he ailerons 5 are mounted on horns 6; the ailerons being pivoted at 'I on the horns 6. The ailerons have attached to their upper surface horns 8 to which are pivoted at 9 the aileron control rods I0. Empennage 4surfaces are indicated at 4.

The aileron control rods I0 are pivoted at II, as diagrammatically illustrated in Figure 1, to a control member I2, which is pivoted` at I3. 'I'he control member I2 is provided with two arms I4 and I5, indicated in dotted lines. The arms I4- arefconnected by a cable I 6 and the arms I5 are connected by a cable I1. The cable I'l passes over pulleys I8 andis attached to a control stick I9. 'I'he aileron control mechanism is of the well known type and the details of construction are not given herein.

Spaced from the upper front edge of the aileron 5 is an element 2l) which has a curved front surface and is so shaped at its rear as to provide a substantially parallel slot 2| which slopes backwardly and upwardly above the upper leading edge of the aileron 5. The element 20 is supported inV its spaced relationship to the upper leading edge oi' -the aileron 5 by means of support elements 22, only one of which is shown.

Referring to Fig. 3, -I have shown a graph in which ,the control stick forces in pounds necessary to accomplish a certain movement of a pair of Zap ailerons in minus or plus directions from the neutral position are indicated. The dotted line indicates the action of a pair of Zap ailerons placed as shown in Fig. 2, .but without the slotted front construction just described. The unbroken line on the graph indicates the stick forces plotted with respect to a pair of Zap ailerons with leading edge xed slots. Both lines approximate actual performance. y From an inspection of the dotted line in Fig. 3, it will be seen that for the first few degrees of movement of the pair of ailerons from their neutral position the `feel on the control stick is what is known to pilotsas soupy. The forces necessary to move the pair of ailerons then become sharply greater, and at about ten degrees in the ,particular graph shown, the force to move an ordinary pair of Zap ailerons not provided with the leading edge fixed slot is about thesame asV that to move a pair of Zap lailerons provided with the leading edge fixed slot. From ten degrees on the forces required to move the pair of ailerons to increase minus and plus angles of attack are very much greater than is the case with the pair olf tZap ailerons provided with the leading edge s o With the form of aileron just described, I have found that in certain instances lift increase on the positive aileron is between 18 and 20 per cent, and this produces a rolling moment on the whole airplane which gives an increase of about 10 per cent in total rolling moment over the conventional pair of Zap ailerons. Furthermore, it

is possible to balance the ailerons considerably farther aft which will permit exceedingly light stick forces and, therefore, lighter mechanism. Conversely, Zap ailerons, not equipped with the flap, when given a pivot point such that there is a. favorable location for balance, so that negative hinge moments which might cause flutter are largely eliminated, have, in certain instances, high stick forces. Because of vhigh stick forces, the rapid control of the airplane is in some instances somewhat dlmcult.

With the conventional Zap aileron it was found that with the point of pivot about 22 to 25 per cent back from the leading edge, a flutter sometimes occurred at low angles because of negative hinge moments. When the pivot point was moved up to about 18 per cent, the flutter was eliminated but stick forces tended to become largebecause of the forward location of the pivot.

When using the type of aileron with the fixed mening edge slot construction just described,

there are numerous advantages. advantages are that;

1) The pivot point of the aileron een be moved to the rear, preventing fluttering;

(2) Due to relatively great `rearward move- .ment of the pivot favorable hinge moments are Some of the lin Figs. 1 to 8, namely pair at obtained, i. e. stick forces are such that the pilot i 24 to the trailing edge of the aileron 5e The supplemental airfoil 23 is provided with a horn 25 to which is pivoted at 26 a link 21 whose other end is pivoted at 28 to the supporting horn 6 for the aileron 5.

In Fig. 5 the interior construction of the aileron 5is shown, which is similar to the forms shown there is a front hollow bracing tube 29 having supports 3l pivoted at 1 on the upper tip of the horn 6. There are provided slots 33 to permit the horns 6 to pass into the interior of the aileron 5. The position of the aileron 5 with respect a construction in which to the flap or supplemental airfoil 23 in varying positions is shown in dotted lines in Fig. 5.

Here the supplemental airfoil or flap 23 and the linkage indicated causes a phenomenon similar to that in the form of aileron shown in Fig. 2, namely a reduction in the hinge moment of the high plus and minus angles of attack. Moreover, the nap increases the rolling moment of the pair due to the down aileron.

In the form of aileron shown in Fig. 6, the aileron 5 is provided with a split flap type of construction in which there is la flap 34 pivoted at 35 to the lower rear surface of the aileron 5. It is to be noted that the aileron 5 is of the single cambered type witli a cambered upper surface.

The fiap,34 in its up position forms a continuation of the lower surface of the aileron and has its trailing edge substantially adjacent the trailing-edge of the aileron. Projecting into the interior of the aileron 5`is a horn 36 fastened t0 the upper front surface of the flap 34. Pivoted to the horn at 31 is a link 38 whose other end is provided with a, slot construction 39 which-fits over a pivot 4I provided on the support arm 6. Therev K is provided a spring 42 attached at 43 to some suitable portion of the interior of the aileron 5 at one end, and. at the other end attached to the horn 36 on the iiap 34'.

The spring 42 is a tension spring and tends to hold the iiap 34 in the position indicated in as indicated in dotted lines in Fig. 6. This form of construction is peculiarly adapted to a single cambered aileron and tends to decrease the hinge moments of the pair at high plus and minus angles of attack and to increase the rolling moment of the pair due to the down aileron.

In Fig. I I have shown a construction somewhat similar, to that shown in Fig. 6. The aileron 5, however, is of the double cambered type and there is provided a. flap 44 pivoted at 45 on the upper surface of the aileron 5. The trailing edge of the flap lies substantially adjacent and just above the trailing edge of the aileron. The lower front edge 75 interior of the aileron of the iiap 44 is provided with a horn 48 to :edge of the aileron is lowere at 56 .to the upper side 'ture 63 which 'of aileron shown, rthe linkages and constructions 1:ervaar-1 which is pivoted at 4'1 the link 38 which is identical i'n 'construction with the link 38 of the construction shown inv Fig. 6. A spring 48 'is attached to the flap horn 46, and also attached at 49 to the interior of the aileron 5.

In the up position of the aileron shown in Fig. 'I there is no movement of the flap since the slotted portion 39 of the link 38 slides over the pivot 4|, and the spring 48 holds the iiap shut. In the down movement of the aileron, when the trailing however, the pivot 4| strikes the end of the slo 39 and the flap 44 is opened against the tension of the spring 48. The hinge moments at high plus and minus angles of attack are reduced so that the stick forces approximate those indicated in the unbroken lineof the graph, Fig. 3.

' In Fig. 8 I have shown the aileron 5 as single cambered with relatively at lower 'surface and a cambered upper surface. The aileron 5 is provided with a ilap 5| Whose: trailing edge lies adjacent and just below the trailing edge of the aileron C The iiap.5| is provided with an attachment member 52, which is pivoted on a pivot member 53 which is also pivoted to the link 3,8. The pivot 53 is adapted to pass through and slide in a slot 54 formed in a bracing rib 55 of the aileron. Pivoted of the ap Slis a. link 5'| which is also pivoted at' its other end 58 to the interior of the aileron construction.

The link'38 is adapted to pass through an aper- 'ture 59 formed in the lower surfaceof the aileron 5. In up positions of the aileron, as show n in Figi 8, there is a spring 59 attached at 6| tothe` .5 and attached at-its other which prevents the iiap 5| end to the support 52 from opening. .l Y

However, when'the aileron is lowered (its trail-1 ing edge `lowered) the pin 4| engages thevend of l,the slot 39 in the link 38 and forces the iiap to a iiown position withrespect to the aileron,y as indicated in dotted lines. The lengths of linkage and .points of pivoting are such as to cause the trailing edge of the ap to lie substantially in the locus of A perpendicular's drawn tothe datum lines of the aileron sections whichpass .through the tr y 4 edge of the aileron. This type of ap is called a Zap and I have found it of peculiar utility in gcpnnection with iFigure 8.

the type of aileron shown in With the form of aileronsdepicted in Fig. 8 i ere is .an increased rolling moment and a reduc` tion in hinge moments for the pair at high plus jana minus angles of attack.

In Figure 9 I` have shown anjaileron 5 provided f with .a slot 62 formed inan interior bracing struc. is attached to the front.- hollow bracing tube 29. A pivot 54,'carried on the upper.

end of the support horn 6, passes through the slot 52 formed in the member 63. Pivoted to the member '63 uat 85 is a link- .which is pivoted at 81 -on the aileron horn' 8. The

' link 66 passes through an aperture 88 in the lower l surface of the aileron 5. A

It will be *understood that in all of these forms are"`duplicated adjacent the horns 6. and that is true of this construction' as well. e

In Figure 9 there is shown in dotted-lines the ,movement of the aileron in its up and down podrtions.l In the up position of the aileron the linkagecauses theaileron to move bodily forward on the-horn 6.v In the down movement of the ailerthe aileron moves bodily backward on the horn `portion vofthe aileron shifts in side of the Acraft and by there is a substantially and mlm@ not intended to represent accurately the action which occurs in the case of every aileron pair, but is merely indicative of what may be, Within reasonable limits of error, expected of the ailerons shown in this application.

In Figure -10 I have shown the aileron 5 attached to a support andslopes backward. The -support 10 is pivoted at its lower rear end to a pivot 1| formed on a support horn 12 which has a relatively great the moment of -10 which'is relatively long backward angular slope with respect to the upper surface of the wings 4. They aileron control rod I0 is pivoted at 13 to a front part of the support 10. With this arrangement the aileron is pivoted on the horn 'l2 at a point well below and behind the normal with respect to its hinged point 7| is shown in dotted lines and the construction is such that the shift in center of pressure on the pair of ailerons'is compensated for by change in the .moment arm from the center of pressure to the pivots, so that the stick forces necessary to operate the pair of ailerons are within the limits of tolerancerepresented by the unbroken linein Fig.3.-. f

In Figs. 11 and 12 I have shown an aileron -of warped construction. In Figs. 11 and .12 the trailing edge-of the aileron is indicated by the line 15. The aileron is parent from these two gures A line 'I6 indi'- cates the trailing edge of the wing 4. This warped construction is such that when the center of pressure on' one portion of the area shifts in one direction, thecenter of pressure on the other the other direccenter of pressure of the l aileron. T'he different positions of the aileron warped, as is clearly ap' tion, and the sum of the center of pressure on the two areas on each aileron in the-pair tends to permit the stick forces for the pair to approximate the unbroken -line shown in the graph,

I claim:

1. In an aircraft having a transverse wing extendingon either side of the lcenter line of the craft and roll control mechanism including a control member, roll mounted on said wing.- connections between said control member to said devices, straight line increasein forces necessary to move the controlmember as the roll producing devices are moved from their 2. An aircraft roll control mechanism comprising'a' control member.. a roll producing device, operating connections between the control member and the roll producing device, and-means where- Astraight line increase in forces necessary jtomove ,the control member as the rollneutral position.

' 3.- In an aircraft having a transverse wingextending on either side of the center line .of the producing device is moved from its 0 producing devices on either and means'whereby there is a substantially neutral positions.

craft and `roll control mechanism including a control member, ailerons on yeither side of the craft on said-wingconnections between 'said control member jto said ailerons, and means -whereby there is a substantially straight line increase in forces necessary. to move the control member as the ailerons are moved from their Aneutral positions.

`fi. An aircraft roll control mechanism comprising a control member, an aileron having a fixed slot,-operating connections between the control member and the aileron, and means whereby there is a substantially straight line increase in forces necessary to move the control member as 'the aileron is moved fromits neutral position. 5. In an aircraft having a transverse wing extending on either side of the center line of the craft.,and roll control mechanism including 'a control member. interlinked single cambered ailerons havingmambered upper surfac on either lsideof the craft and mounted on said wing. connections between Vsaid control member to said ailerons, and means including flxedslots located at the forward edge of each aileron whereby there is a substantially straight line increase in forces necessary to move the control memb'er as [the ailerons are moved from ltheir neutral position. l

- 6. In an'aircraft having a transverse wing extending on either side'of the center line of the craft and roll control mechanism including acontrol member on either side of the craft and mountedy on said wing and above the upper surface thereof, connections between said control member to said ailerons, and means whereby Y' there is a substantially straight line increase in forces necessary to move the control member as the ailerons are moved from their neutralposition. 1 Y

7. Ailerons having warped so that upon movement of the pair to angular positions from theneutral the center of pressure with re- 4Q spect to designed areas on Keach aileron shifts so that. the stick forces required to move the pair of ailerons'ffto relatively large plus and minus angles from the neutral increase in substantially 5 9. In a pair of ailerons, relatively long aileron 55 pressure of the pair is compensated for by change.

00 alength direct proportion to theangular movement.

Y 8. A pair of warped ailerons whose center oi pressure shifts are such in varying' positions of up and down movementof the pair as to permit the stick 'forces to increase in substantially straight line fashion.

`S31Dp0rts, baclrwardly sloping horns, pivots on the horns on. which the supports are pivoted. the supports being of such alength and so related to v the ailerons and the horns that shift in center of in the momentarms to the pivots.

10. In a pair of ailerons, yaileron supports.

aileron horns, pivots on the horns on' -which the supports are pivoted, the supports .being of such and so related to the ailerons and the horns that aivaova -V is for by change in the movement v porting horn 'aileron bodily with respect to the pivot is effected in moving from the neutral position.

- aileron and having withresvecttotheaileron. shlftincenterofpressureofthepair r Y.

arms-to the pivots.

11. An aileron having a slot therein, for the aileron mounted in the slot, a supporting horn for the aileron carrying the pivot, a link pivoted on the aileron at one end and on the supat the other whereby moving the 13. An aileron having a slot therein, a pivot for the aileron' mounted in the slot. linkage for shifting the axis of pivoting the pivot during pivoting.

13. In a pair of slotted ailerons, pivots for the ailerons mounted in the slots, means for so moving the aileron Aon the pivots while moving through up and 'down podtions as to compensate for shifts in center of pressure vby varying the moment arms aboutthe pivots. l

14. A single eambered aileron comprising a flap on the lower rear surface ofthe aileron adapted to have nstramns edge in 'positions or extension of perpendiculars to the datum lines of the air- .foil sections of the aileron and passing through the trailing edge of the aileron, a horn on the flap. a spring within the from the neutral I a pivot of the aileron aboutv aileron attached to the interior thereof at one end and at its other end to the horn on the flap, and a link pivoted to the `horn at one end to a pivot nxed with' respect to the aileron.

15. A single eambered aileron comprising a flap on the lower rear surface of the aileron adapted to have its trailing and retraction lie substantially within the locus of perpendioulars to the datum -lines of the airfoil secidonsof the aileron and passing through the trailing edge of the aileron, linkages to cause ldownward movement of the flap 'with respect to the aileron on Vdownward movement of the aileron.

16. A double eambered aileron comprising a flap plvoted on the upper rear surface of the its trailing edge in its readjaoent the trailing edge of the a spring within the tracted position aileron, a horn on the flap.

` aileron attached to the interior thereof at one end and at its other end to the horn on the flap, and a link' pivoted alidablyllnvoted at its other end to a pivot xed -witl'rrespect to the aileron.

aileronandhavingitstrailingedgeinits-reend and slidably pivoted at its other edge in positions of extension.

surface`of the.

to the horn at one ,endfand adjacent the trailing edge of the m. a nom n the nap. a spring within uie aileron attached to end'andatits other and a link #voted to dimly-pleated aufs the hornat one end and other` end Ato a pivot 'fixed the interior thereof at 'one end to the horn on theiiap, 

